High-crystallinity spherical silicon carbide powder as well as preparation method and application thereof

Abstract

The invention belongs to the technical field of material preparation, and discloses high-crystallinity spherical silicon carbide powder and a preparation method and application thereof.The method comprises the steps that tetraethyl silicate and 4-phenylbutyltrimethoxysilane are dissolved in absolute ethyl alcohol, a catalyst is added, and a uniform mixed solution is obtained after stirring; heating the mixed solution in a water bath at 25-35 DEG C, stirring and dropwise adding ammonia water, stopping dropwise adding ammonia water when the mixed solution becomes milk white, heating in a water bath at 50-60 DEG C, and centrifuging and washing the obtained product to obtain a spherical silicon-carbon mixture; and sintering the mixture at 1500-1600 DEG C in a protective atmosphere, and grinding to obtain the high-crystallization spherical silicon carbide powder with the average particle size of 2.6-5.5 microns and the crystallinity of 92% or above. The spherical silicon carbide powder disclosed by the invention has the advantages of easily available raw materials, simple process, high crystallinity and excellent comprehensive performance, and can be widely applied to the fields of electronics and photoelectricity.

Description

Technical Field

[0001] The present invention belongs to the technical field of material preparation, and more specifically, relates to a highly crystalline spherical silicon carbide powder and a preparation method and application thereof. Background Art

[0002] As an important semiconductor material, silicon carbide is widely used in the power electronics industry. With the rapid development of power electronics technology, the performance requirements for semiconductor materials are also constantly increasing. Silicon carbide has become a popular material for power electronic devices with its excellent physical and chemical properties, such as high hardness, high melting point, high thermal conductivity, and radiation resistance. Especially under extreme conditions such as high temperature, high pressure, and high power density, the advantages of silicon carbide materials are more obvious. Therefore, the research on spherical silicon carbide is particularly important in this context.

[0003] The preparation of spherical silicon carbide materials has very important application value in industry. In addition, the excellent properties of silicon carbide such as high strength, high hardness, high thermal conductivity, and low thermal expansion coefficient largely depend on its high crystallinity. It is very necessary to prepare spherical silicon carbide with high crystallinity. Silicon carbide powder is the basic raw material for preparing silicon carbide ceramics and films. Its preparation methods include: mechanical crushing method, carbon thermal reduction method, thermal decomposition method, sol-gel method, vapor deposition method, etc. At present, the preparation process of spherical silicon carbide is complicated and costly, and it cannot be produced stably in large quantities. The silicon carbide powders currently prepared are mostly irregular in shape, and most of them have sharp edges and corners, which are not conducive to flow, resulting in limited development of its application in fillers. Spherical / true spherical particles have good fluidity and obvious dispersion effect due to the minimum friction between particles. The spherical particle powder is evenly distributed in all directions, so the mechanical, thermal, and electrical properties in all directions are basically consistent. Summary of the invention

[0004] In order to solve the above-mentioned deficiencies and shortcomings of the prior art, the primary purpose of the present invention is to provide a method for preparing highly crystalline spherical silicon carbide powder. The method adopts a sol-gel method to adjust the ratio of tetraethyl silicate and 4-phenylbutyltrimethoxysilane, water bath heating reaction conditions, and obtains highly crystalline (crystallinity of more than 92%) spherical silicon carbide powder after high temperature sintering.

[0005] Another object of the present invention is to provide highly crystalline spherical silicon carbide powder prepared by the above method, wherein the silicon carbide powder has good sphericity and particle size.

[0006] The purpose of the present invention is achieved through the following technical solutions:

[0007] A method for preparing highly crystalline spherical silicon carbide powder comprises the following steps:

[0008] S1. dissolving tetraethyl silicate and 4-phenylbutyltrimethoxysilane in anhydrous ethanol, adding a catalyst, and stirring to obtain a uniform mixed solution;

[0009] S2. The mixed solution was heated in a water bath at 25 to 35°C, stirred and ammonia was added dropwise, and the addition of ammonia was stopped when it turned milky white, and heated in a water bath at 50 to 60°C. The obtained product was centrifuged and washed to obtain a silicon-carbon mixture;

[0010] S3. The silicon-carbon mixture is sintered at 1500-1600° C. in a protective atmosphere, and after grinding, a highly crystalline spherical silicon carbide powder is obtained, the crystallinity of which is above 92%.

[0011] Preferably, the molar ratio of tetraethyl silicate, 4-phenylbutyltrimethoxysilane and the catalyst in step S1 is 1:(0.67-2):0.33.

[0012] Preferably, the volume ratio of the total mole of tetraethyl silicate and 4-phenylbutyltrimethoxysilane in step S1, the volume of anhydrous ethanol and the volume of ammonia water in step S2 is (0.1-0.18) mol: (29.14-36.3) mL: (6.6-13.2) mL.

[0013] Preferably, the catalyst in step S1 is hydrochloric acid or acetic acid.

[0014] More preferably, the concentration of the catalyst is 0 to 0.003 mol / mL.

[0015] Preferably, the concentration of the aqueous ammonia in step S2 is 18-25 wt %.

[0016] Preferably, the stirring speed in step S2 is 300-400 rpm; the heating time in a water bath at 25-35° C. is 2-3 h, and the heating time in a water bath at 50-60° C. is 18-24 h.

[0017] Preferably, the protective atmosphere in step S3 is nitrogen or argon; and the sintering time is 2 to 4 hours.

[0018] A highly crystalline spherical silicon carbide powder is prepared by the method, and the average particle size of the silicon carbide powder is 2.6-5.5 μm.

[0019] The highly crystalline spherical silicon carbide powder is used in the field of electronic packaging.

[0020] Compared with the prior art, the above technical solution has the following beneficial effects:

[0021] 1. The present invention adopts a sol-gel method to control the sphericity and particle size of silicon carbide by adjusting the ratio of tetraethyl silicate and 4-phenylbutyltrimethoxysilane and the water bath heating reaction conditions; and obtains silicon carbide powder with high crystallinity by adjusting the atmosphere, temperature and time of high-temperature sintering;

[0022] 2. The spherical silicon carbide powder of the present invention has high crystallinity (crystallinity is above 92%), good sphericity and particle size (average particle size is 2.6 to 5.5 μm), and can significantly improve the fluidity of the silicon carbide powder. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 This is a scanning electron microscope photograph of highly crystalline spherical silicon carbide particles prepared in Example 2;

[0024] Figure 2 This is the XRD pattern of the highly crystalline spherical silicon carbide particles prepared in Example 2. DETAILED DESCRIPTION

[0025] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the drawings in the embodiments of the present invention. The embodiments described herein are only used to illustrate and explain the present invention, but should not be understood as limiting the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0026] Example 1

[0027] 1. Dissolve 0.06 mol of tetraethyl silicate and 0.04 mol of 4-phenylbutyltrimethoxysilane in 29.14 mL of anhydrous ethanol, and then add 0.02 mol of hydrochloric acid diluted with 7.2 mL of water to obtain solution A;

[0028] 2. Place solution A in a flask and heat it in a water bath at 50°C for 3 hours, stir at 300 rpm, lower the water bath temperature to 30°C, add 25 wt% ammonia water until the solution turns milky white, and stir for 24 hours; centrifuge the resulting solution, wash it twice with ethanol, once with water, and dry it to obtain a carbon-silicon mixture powder;

[0029] 3. The carbon-silicon mixture powder was heated to 1600°C at 10°C / min in a high-purity argon environment, kept warm for 2 hours, cooled to room temperature and then ground to obtain highly crystalline spherical silicon carbide powder with an average particle size of 5.5 μm and a crystallinity of 92.3%.

[0030] Example 2

[0031] 1. Dissolve 0.06 mol of tetraethyl silicate and 0.04 mol of 4-phenylbutyltrimethoxysilane in 29.14 mL of anhydrous ethanol, and then add 0.02 mol of hydrochloric acid diluted with 7.2 mL of water to obtain solution A;

[0032] 2. Place solution A in a flask and heat it in a water bath at 50°C for 3 hours, stir at 400 rpm, lower the water bath temperature to 30°C, add 25 wt% ammonia water until the solution turns milky white, and stir for 24 hours; centrifuge the resulting solution, wash it twice with ethanol, once with water, and dry it to obtain a carbon-silicon mixture powder;

[0033] 3. The carbon-silicon mixture powder was heated to 1600°C at 10°C / min in a high-purity argon environment, kept warm for 4 hours, cooled to room temperature and then ground to obtain highly crystalline spherical silicon carbide powder with an average particle size of 5.5 μm and a crystallinity of 96.4%.

[0034] Figure 1 This is a scanning electron microscope photograph of the highly crystalline spherical silicon carbide particles prepared in Example 2; Figure 1 It can be seen that the particle size of the highly crystalline spherical silicon carbide is about 5.5 μm. Figure 2 This is the XRD pattern of the highly crystalline spherical silicon carbide particles prepared in Example 2. Figure 2 It can be seen that the main component of the prepared spherical silicon carbide powder is β-crystalline silicon carbide.

[0035] Example 3

[0036] 1. Dissolve 0.06 mol of tetraethyl silicate and 0.08 mol of 4-phenylbutyltrimethoxysilane in 36.3 mL of anhydrous ethanol, and then add 0.02 mol of hydrochloric acid diluted with 7.2 mL of water to obtain solution A;

[0037] 2. Place solution A in a flask and heat it in a water bath at 50°C for 3 hours, stir at 400 rpm, lower the water bath temperature to 30°C, add 25 wt% ammonia water until the solution turns milky white, and stir for 24 hours; centrifuge the resulting solution, wash it twice with ethanol, once with water, and dry it to obtain a carbon-silicon mixture powder;

[0038] 3. The carbon-silicon mixture powder was heated to 1600°C at 10°C / min in a high-purity argon environment, kept warm for 4 hours, cooled to room temperature and then ground to obtain highly crystalline spherical silicon carbide powder with an average particle size of 3.37 μm and a crystallinity of 95.8%.

[0039] Example 4

[0040] 1. Dissolve 0.06 mol of tetraethyl silicate and 0.12 mol of 4-phenylbutyltrimethoxysilane in 36.3 mL of anhydrous ethanol, and then add 0.02 mol of hydrochloric acid diluted with 7.2 mL of water to obtain solution A;

[0041] 2. Place solution A in a flask and heat it in a water bath at 50°C for 3 hours, stir at 400 rpm, lower the water bath temperature to 30°C, add 25 wt% ammonia water until the solution turns milky white, and stir for 24 hours; centrifuge the resulting solution, wash it twice with ethanol, once with water, and dry it to obtain a carbon-silicon mixture powder;

[0042] 3. The carbon-silicon mixture powder was heated to 1600°C at 10°C / min in a high-purity argon environment, kept warm for 4 hours, cooled to room temperature and then ground to obtain highly crystalline spherical silicon carbide powder with an average particle size of 2.64 μm and a crystallinity of 96.1%.

[0043] Comparative Example 1

[0044] 1. Dissolve 0.06 mol of tetraethyl silicate and 0.04 mol of 4-phenylbutyltrimethoxysilane in 29.14 mL of anhydrous ethanol, and then add 0.02 mol of hydrochloric acid diluted with 7.2 mL of water to obtain solution A;

[0045] 2. Place solution A in a flask and heat it in a water bath at 50°C for 3 hours, stir at 300 rpm, lower the water bath temperature to 30°C, add 25 wt% ammonia water until the solution turns milky white, and stir to react for 24 hours; then centrifuge the resulting solution, wash it twice with ethanol, once with water, and dry it to obtain a carbon-silicon mixture powder;

[0046] 3. The carbon-silicon mixture powder was heated to 1500°C at 10°C / min in a high-purity argon environment, kept warm for 4 hours, cooled to room temperature and then ground to obtain spherical silicon carbide powder with an average particle size of 5.5 μm and a crystallinity of 88.3%.

[0047] The spherical silicon carbide powder of the present invention has high crystallinity (crystallinity is above 92%), good sphericity and particle size (average particle size is 2.6-5.5 μm), can significantly improve the fluidity of the silicon carbide powder, and can be used in the field of electronic packaging.

[0048] The above embodiments are preferred implementation modes of the present invention, but the implementation modes of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations and simplifications that do not deviate from the spirit and principles of the present invention should be equivalent replacement methods and are included in the protection scope of the present invention.

Claims

1. A method for preparing highly crystalline spherical silicon carbide powder, characterized in that: The following steps are involved: S1. dissolving tetraethyl silicate and 4-phenylbutyltrimethoxysilane in anhydrous ethanol, adding a catalyst, and stirring to obtain a uniform mixed solution; S2. The mixed solution was heated in a water bath at 25 to 35°C, stirred and ammonia was added dropwise, and the addition of ammonia was stopped when it turned milky white, and heated in a water bath at 50 to 60°C. The obtained product was centrifuged and washed to obtain a silicon-carbon mixture; S3. The silicon-carbon mixture is sintered at 1500-1600° C. in a protective atmosphere, and after grinding, a highly crystalline spherical silicon carbide powder is obtained, the crystallinity of which is above 92%.

2. The method for preparing highly crystalline spherical silicon carbide powder according to claim 1, characterized in that: The molar ratio of tetraethyl silicate, 4-phenylbutyltrimethoxysilane and catalyst described in step S1 is 1:(0.67-2):0.

33.

3. The method for preparing highly crystalline spherical silicon carbide powder according to claim 1, characterized in that: The total mole ratio of tetraethyl silicate and 4-phenylbutyltrimethoxysilane in step S1, the volume of anhydrous ethanol and the volume ratio of ammonia water in step S2 is (0.1-0.18) mol: (29.14-36.3) mL: (6.6-13.2) mL.

4. The method for preparing highly crystalline spherical silicon carbide powder according to claim 1, characterized in that: The catalyst described in step S1 is hydrochloric acid or acetic acid.

5. The method for preparing highly crystalline spherical silicon carbide powder according to claim 4, characterized in that: The concentration of the catalyst is 0 to 0.003 mol / mL.

6. The method for preparing highly crystalline spherical silicon carbide powder according to claim 1, characterized in that: The concentration of the ammonia water in step S2 is 18-25 wt %.

7. The method for preparing highly crystalline spherical silicon carbide powder according to claim 1, characterized in that: The stirring speed in step S2 is 300-400 rpm; the heating time in a water bath at 25-35° C. is 2-3 hours, and the heating time in a water bath at 50-60° C. is 18-24 hours.

8. The method for preparing highly crystalline spherical silicon carbide powder according to claim 1, characterized in that: In step S3, the protective atmosphere is nitrogen or argon; and the sintering time is 2 to 4 hours.

9. A highly crystalline spherical silicon carbide powder, characterized in that: The silicon carbide powder is prepared by the method according to any one of claims 1 to 8, and the average particle size of the silicon carbide powder is 2.6 to 5.5 μm.

10. Use of the highly crystalline spherical silicon carbide powder according to claim 9 in the field of electronic packaging.

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